Change default search engines

[fhd]

Background

We currently have a lot of search engines available by default. We want to reduce this to a less overwhelming amount, and reduce country/locale specific differences.

What to change

In all countries except China, the default search engines should be, in that order:

1. DuckDuckGo
2. Yahoo
3. Google
4. Wikipedia
5. Amazon

China needs a special case, since most Chinese cannot access some or all of these. So just in China, it should be:

1. Baidu
2. DuckDuckGo
3. Yahoo
4. Google
5. Wikipedia
6. Amazon

In either case:

• It's fine to skip search engines currently not available in the specific locales, it should fall back to the next one in the list.
• Only the first three search engines have to be in the order specified, for those below it doesn't matter.

We can surely refine this over time, based on what search engines people in specific countries find particularly useful, but this should do for now.

We should test this to ensure that this change doesn't change anyone's configured search engine. Two cases two consider:

1. If they changed the search engine to something that was previously on the list, but not anymore, e.g. Bing.
2. If they added an additional search engine, e.g. ixquick.
3. If they had a default configured for them that is now not longer available. Yandex for Russian locales might be such a case.